JP2013093268A - Wavelength conversion type light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion type light source device capable of cooling a phosphor layer, and thereby capable of obtaining high light emission efficiency and aiming at downsizing.SOLUTION: The device is provided with an excitation light-incident window member for excitation light to be incident into, a phosphor layer emitting fluorescence on receipt of the excitation light, a fluorescence emission window member for the fluorescence from the phosphor layer to be emitted from, and a light-reflecting member having a light-reflecting face formed for reflecting the excitation light and the fluorescence. A wavelength conversion space is formed where the excitation light and the phosphor cross each other, as it is circumscribed by the excitation light-incident window member, the fluorescence emission window and the light-reflecting face of the light-reflecting member. The phosphor layer is formed on the light-reflecting face of the light-reflecting member inside the wavelength conversion space, the excitation light-incident window member has optical characteristics of transmitting the excitation light and reflecting the fluorescence, and the fluorescence emission window member has optical characteristics of transmitting the fluorescence and reflecting the excitation light.

Description

  The present invention relates to a wavelength conversion type light source device that emits wavelength-converted light by receiving excitation light from an excitation light source.

Conventionally, a short arc type high-pressure discharge lamp has been used as a light source of an image projection apparatus such as a liquid crystal projector. Thus, in recent years, an image projection apparatus using a solid light emitting element such as a light emitting diode or a laser diode as a light source has been proposed, and an image projection apparatus using such a solid light emitting element does not require a high voltage power source. In addition, the solid-state light emitting device as a light source is advantageous in comparison with an image projection apparatus using a high-pressure discharge lamp in that it has a long service life and excellent impact resistance.
However, in the above image projection apparatus, it is necessary to use three types of solid light emitting elements that emit red, green, and blue light, respectively, but there is no solid light emitting element that emits green light with a high light emission amount. It is difficult to obtain a sufficient amount of light as a light source for the image projection apparatus.
For this reason, instead of a solid-state light emitting device that emits green light, a phosphor layer containing a phosphor material that emits green fluorescence upon receiving excitation light (for example, blue light) from an excitation light source is transparent. A wavelength conversion type light source device formed on a conductive substrate is used.

However, since the phosphor substance converts a part of the light energy to heat energy when receiving the excitation light, in the wavelength conversion type light source device, the phosphor layer is locally irradiated with the excitation light. Then, as a result of the phosphor generating heat at a high temperature, there is a problem that the light emission efficiency is lowered.
In order to solve such a problem, there is provided a wavelength conversion type light source device including a light emitting wheel in which a phosphor layer is formed on a circular substrate made of glass or the like, and a rotation driving mechanism that rotationally drives the light emitting wheel. It has been proposed (see Patent Document 1). According to such a structure, since it is avoided that excitation light is locally irradiated to a fluorescent substance layer, it can suppress that luminous efficiency falls.

  However, in the above conversion type light source device, it is necessary to mount a light emitting wheel having a large area and a rotation driving mechanism for rotating the light emitting wheel, so that the structure of the entire device is complicated and large. There is a problem.

JP 2010-237443 A

  The present invention has been made based on the circumstances as described above, and an object of the present invention is to cool the phosphor layer, whereby high luminous efficiency can be obtained and the size can be reduced. It is an object of the present invention to provide a wavelength conversion type light source device capable of achieving the above.

The wavelength conversion type light source device of the present invention is a wavelength conversion type light source device that receives excitation light from an excitation light source and performs wavelength conversion.
From the excitation light incident window member into which the excitation light from the excitation light source is incident, a phosphor layer that emits fluorescence upon receiving the excitation light incident through the excitation light incident window member, and from the phosphor layer A fluorescence emission window member from which the fluorescence is emitted, and a light reflection member on which the excitation light and a light reflection surface for reflecting the fluorescence are formed, the excitation light incidence window member, and the fluorescence emission window By being surrounded by the light reflecting surface of the member and the light reflecting member, a wavelength conversion space where the excitation light and the fluorescence intersect is formed,
The phosphor layer is formed on a light reflecting surface of the light reflecting member in the wavelength conversion space,
The excitation light incident window member has an optical characteristic of transmitting the excitation light and reflecting the fluorescence, and the fluorescence emission window member has an optical characteristic of transmitting the fluorescence and reflecting the excitation light. It is characterized by having.

In such a wavelength conversion type light source device, the light reflecting member is a cylindrical member having a light reflecting surface formed on an inner peripheral surface, and the excitation light is blocked so as to close the openings at both ends of the light reflecting member. It is preferable that the incident window member and the fluorescence emitting window member are disposed.
The light reflecting member has a recess having a light reflecting surface formed on the inner surface and a through hole that communicates with the recess, and the excitation light incident window is configured to close the opening of the through hole of the light reflecting member. It is preferable that the fluorescent light emission window member is disposed so as to close the opening of the concave portion of the light reflecting member.

Further, the wavelength conversion type light source device of the present invention is a wavelength conversion type light source device that receives the excitation light from the excitation light source and converts the wavelength.
A light reflecting member having a recess having a light reflecting surface formed on the inner surface, and excitation light from an excitation light source disposed so as to close the opening of the recess of the light reflecting member and fluorescence from a phosphor layer described later A light reflecting member formed with a window member from which light is emitted, a phosphor layer that receives excitation light incident through the window member and emits fluorescence, and a light reflecting surface that reflects the excitation light and the fluorescence And is surrounded by a light reflecting surface in the window member and the light reflecting member, thereby forming a wavelength conversion space where the excitation light and the fluorescence intersect,
The phosphor layer is formed on a light reflecting surface of the light reflecting member in the wavelength conversion space,
The window member has an optical characteristic of reflecting the excitation light in an angle range greater than a specific incident angle.

  In such a wavelength conversion type light source device, it is preferable that the window member has an optical characteristic of reflecting the fluorescence in an angle range equal to or greater than another specific incident angle.

In the wavelength conversion light source device of the present invention, the light reflecting member preferably has thermal conductivity.
The phosphor material constituting the phosphor layer preferably emits fluorescence upon receiving excitation light in a blue region having a wavelength of 445 nm or less.

  According to the wavelength conversion type light source device of the present invention, since the phosphor layer is formed on the light reflection surface of the light reflection member that forms the wavelength conversion space where the excitation light and the fluorescence intersect, the light reflection member is configured. By using a material having thermal conductivity as the material to be used, it is possible to exhaust heat generated in the phosphor layer to the outside through the light reflecting member, and thus the phosphor layer can be cooled. Therefore, high luminous efficiency can be obtained. In addition, since it is not necessary to mount a light emitting wheel or a rotation mechanism for rotating the light emitting wheel, the apparatus can be reduced in size.

It is sectional drawing for description which shows the structure of the principal part of the wavelength conversion type light source device which concerns on the 1st Embodiment of this invention. It is a spectral reflectance curve figure which shows typically the spectral reflection characteristic in an example of the window member for excitation light incidence. It is a curve figure which shows the temperature characteristic in each of (beta) -sialon type | system | group fluorescent substance and a silicate type | system | group fluorescent substance. It is explanatory drawing which shows the structure of the wavelength conversion type light source device which concerns on the 2nd Embodiment of this invention, (a) is a perspective view of a wavelength conversion type light source device, (b) is the principal part in a wavelength conversion type light source device. FIG. 6C is a front partial cross-sectional view showing the main part of the wavelength conversion type light source device by cutting, and FIG. 8D is a side cross-sectional view showing the main part of the wavelength conversion type light source device by cutting. It is sectional drawing for description which shows the structure of the principal part of the wavelength conversion type light source device which concerns on the 3rd Embodiment of this invention. It is a spectral reflectance curve figure which shows typically the spectral reflection characteristic in an example of a window member. It is a spectral reflectance curve figure which shows the spectral reflection characteristic in the window member used for the wavelength conversion type light source device which concerns on an Example. It is explanatory drawing which shows the structure of the measurement system for measuring the light quantity of the fluorescence radiate | emitted from the window member in the wavelength conversion type light source device which concerns on an Example. Surface temperature of the phosphor layer obtained by simulating the surface temperature of the phosphor layer when the thickness of the phosphor layer is changed by thermal structure analysis based on the wavelength conversion type light source device according to the example It is a graph which shows the relationship between thickness with a fluorescent substance layer.

Hereinafter, embodiments of the wavelength conversion type light source device of the present invention will be described.
FIG. 1 is an explanatory cross-sectional view showing a configuration of a main part of the wavelength conversion type light source device according to the first embodiment of the present invention. This wavelength conversion type light source device receives the excitation light L1 from the excitation light source and converts the wavelength, and reflects the excitation light L1 from the excitation light source and the fluorescence L2 from the phosphor layer 20 described later on the inner peripheral surface. A rectangular cylindrical light reflecting member 10 having a light reflecting surface 10a is provided. In the light reflecting member 10 of this example, the light reflecting layer 12 is formed on the inner peripheral surface of the cylindrical base 11, and the light reflecting surface 10 a is formed by the light reflecting layer 12.
At both ends of the light reflecting member 10, a rectangular plate-shaped excitation light incident window member 15 into which excitation light L1 from an excitation light source is incident and a rectangular plate from which fluorescence L2 from a phosphor layer 20 described later is emitted. The fluorescent emission window members 16 are arranged so as to close the openings at both ends of the light reflecting member 10 in a state of facing each other through the cylindrical hole of the light reflecting member 10.

Then, by being surrounded by the light reflecting surface 10a of the excitation light incident window member 15, the fluorescence emission window member 16, and the light reflecting member 10, the excitation light L1 from the excitation light source and the fluorescence from the phosphor layer 20 described later are provided. A wavelength conversion space S where L2 intersects is formed. On the light reflecting surface of the light reflecting member 10 in the wavelength conversion space S, a phosphor layer 20 that receives the excitation light L1 from the excitation light source and emits fluorescence L2 is formed.
Further, of the four planes forming the outer peripheral surface of the light reflecting member 10, a heat exhausting member 25 such as a heat radiating fin is provided on one plane (the lower surface in FIG. 1) so as to contact the light reflecting member 11. It has been.

As a material constituting the cylindrical substrate 11 in the light reflecting member 10, it is preferable to use a material having good thermal conductivity, for example, a material having a thermal conductivity of 100 W / m · K or more. It is preferable to use a highly thermally conductive metal material such as aluminum or copper, or a ceramic material such as AlN.
As the light reflection layer 12, a layer made of a highly light reflective metal material such as silver or aluminum, or a layer formed by depositing fine particles of AlN having a particle size of the order of microns can be used. As a method of forming the light reflecting layer 12, an electrolytic plating method, a vapor deposition method, or the like can be used.

  As the excitation light L1 incident on the excitation light incident window member 15, light in a blue region having a wavelength of 445 nm or less is preferably used. As the excitation light source that emits such excitation light L1, a blue light emitting diode or a blue laser diode can be used.

The excitation light incident window member 15 has an optical characteristic of transmitting the excitation light L1 from the excitation light source and reflecting the fluorescence L2 from the phosphor layer 20. As such an excitation light incident window member 15, a member in which a dielectric multilayer film made of TiO ₂ and SiO ₂ is formed on the surface of a plate-like translucent substrate can be used.
For example, when the excitation light L1 is light in a blue region having a wavelength of 445 nm or less and the fluorescence L2 from the phosphor layer 20 is light in a green region having a wavelength of 500 to 570 nm, the excitation light incident window member 15 used A spectral reflection characteristic is schematically shown in FIG. In the spectral reflectance curve diagram of FIG. 2A, the vertical axis indicates the spectral reflectance (%), and the horizontal axis indicates the wavelength (nm) of incident light. The excitation light incident window member 15 exhibits good transparency with respect to light having a wavelength of 445 nm and exhibits good reflectivity with respect to light with a wavelength of 500 to 570 nm.

The fluorescence emission window member 16 has an optical characteristic of transmitting the fluorescence L2 from the phosphor layer 20 and reflecting the excitation light L1 from the excitation light source. As such a fluorescence emission window member 16, a member in which a dielectric multilayer film made of TiO ₂ and SiO ₂ is formed on the surface of a plate-like translucent substrate can be used.
For example, when the excitation light L1 is light in a blue region having a wavelength of 445 nm or less and the fluorescence L2 from the phosphor layer 20 is light in a green region having a wavelength of 500 to 570 nm, the spectrum of the fluorescence emission window member 16 used is used. The reflection characteristics are schematically shown in FIG. In the spectral reflectance curve diagram of FIG. 2B, the vertical axis represents the spectral reflectance (%), and the horizontal axis represents the wavelength (nm) of incident light. The fluorescence emission window member 16 exhibits good reflectivity with respect to light having a wavelength of 445 nm and exhibits good transparency with respect to light with a wavelength of 500 to 570 nm.

As the phosphor layer 20, for example, a binder resin made of a silicone resin and containing a phosphor substance can be used.
As the phosphor material constituting the phosphor layer 20, an excitation light L1 from an excitation light source, for example, a material that emits fluorescence L2 upon receiving light in a blue region having a wavelength of 445 nm or less is used, and in particular, green having a wavelength of 500 to 570 nm. What emits the fluorescence L2 of an area | region is preferable. As such a phosphor substance, a β-sialon phosphor, a silicate phosphor, and a YAG phosphor are used because they have heat stability that allows high intensity fluorescence L2 to be emitted even at relatively high temperatures. In particular, β-sialon phosphors are preferred.

  FIG. 3 is a curve diagram showing temperature characteristics of each of the β-sialon phosphor and the silicate phosphor. In FIG. 3, the vertical axis indicates the emission intensity (relative value) of the phosphor, the horizontal axis indicates the temperature (° C.) of the phosphor, the curve a relates to the β-sialon phosphor, and the curve b indicates the silicate phosphor. The thing concerning is shown. As shown in this figure, it is understood that both the β-sialon phosphor and the silicate phosphor emit high intensity fluorescence when the temperature is 100 ° C. or lower.

The thickness of the phosphor layer 20 is preferably 75 μm or less, more preferably 30 to 55 μm. When the thickness of the phosphor layer 20 is too small, it may be difficult to emit high intensity fluorescence L2. On the other hand, when the thickness of the phosphor layer 20 is excessive, the heat resistance in the thickness direction of the phosphor layer 20 increases, so that the heat generated in the phosphor layer 20 is efficiently transmitted to the light reflecting member 10. Can be difficult.
In addition, the phosphor layer 20 may contain, for example, thermally conductive particles made of Al ₂ O ₃ , MgO, etc., whereby the heat generated in the phosphor layer 20 can be efficiently reflected by the light reflecting member. 10 can be transmitted.

In the wavelength conversion type light source device described above, the excitation light L1 from the excitation light source is incident on the excitation light incident window member 15 through, for example, the focusing lens 3 and directly or through the wavelength conversion space S. After being reflected by the light reflecting surface 10a of the window member 16 or the light reflecting member 10, the phosphor layer 20 is irradiated. Then, by irradiating the phosphor layer 20 with the excitation light L1, fluorescence L2 having a longer wavelength than the excitation light L1 is emitted from the phosphor layer 20. Of the fluorescence L2, the light traveling toward the fluorescence emission window member 16 is emitted to the outside from the fluorescence emission window member 16, and the light traveling toward the light reflection member 10 is excited by the light reflection member 10 or the excitation. After being reflected by the light incident window member 15, the light is emitted to the outside from the fluorescence emission window member 16.
On the other hand, when the phosphor layer 20 is irradiated with the excitation light L1 from the excitation light source, a part of the energy generated by the excitation light L1 is converted into thermal energy in the phosphor layer 20, so that the phosphor layer 20 is heated. Although generated, the heat generated in the phosphor layer 20 is transmitted from the phosphor layer 20 to the exhaust heat member 25 through the light reflecting member 10, and is exhausted to the outside by the exhaust heat member 25. Thus, the phosphor layer 20 is cooled.
In the above, when a β-sialon-based phosphor or a silicate-based phosphor is used as the phosphor material constituting the phosphor layer 20, the temperature of the phosphor layer 20 is maintained at 100 ° C. or lower. It is preferable that the light reflecting member 10, the phosphor layer 20, and the exhaust heat member 25 are designed.

According to the above wavelength conversion type light source device, since the phosphor layer 20 is formed on the light reflection surface 10a in the light reflection member 10 that forms the wavelength conversion space S where the excitation light L1 and the fluorescence L2 intersect, By using a material having thermal conductivity as the material constituting the light reflecting member 10, heat generated in the phosphor layer 20 can be exhausted from the heat exhausting member 25 to the outside through the light reflecting member 10. Therefore, since the phosphor layer 20 can be cooled, high luminous efficiency can be obtained. In addition, since it is not necessary to mount a light emitting wheel or a rotation mechanism for rotating the light emitting wheel, the apparatus can be reduced in size.
The excitation light incident window member 15 has an optical characteristic of transmitting the excitation light L1 and reflecting the fluorescence L2, and the fluorescence emission window member 16 is an optical characteristic of transmitting the fluorescence L2 and reflecting the excitation light. Therefore, a high light utilization rate can be obtained.

  4A and 4B are explanatory views showing the configuration of the wavelength conversion type light source device according to the second embodiment of the present invention. FIG. 4A is a perspective view of the wavelength conversion type light source device, and FIG. 4B is a wavelength conversion type light source. The side view of the principal part in an apparatus, (c) is a front fragmentary sectional view which cuts and shows the principal part in a wavelength conversion type light source device, (d) is the side sectional view which cuts and shows the principal part in a wavelength conversion type light source device It is. The wavelength conversion type light source device receives the excitation light L1 from the excitation light source and converts the wavelength. The excitation light L1 from the excitation light source on the inner surface of the substantially rectangular parallelepiped base 11 and a phosphor described later. Light reflection having a quadrangular pyramid-shaped concave portion D formed with a light reflecting surface 10a that reflects the fluorescence L2 from the layer 20 and having a through hole K that communicates with the concave portion D from one side surface perpendicular to one surface of the substrate 11. A member 10 is provided. In the light reflecting member 10 of this example, a light reflecting layer (not shown) is formed on the inner surface of the recess D of the base 11, and the light reflecting surface 10a is formed by this light reflecting layer. On one side surface of the substrate 11 in the light reflecting member 10, a rectangular plate-shaped excitation light incident window member 15 into which the excitation light L1 from the excitation light source is incident is disposed so as to close the through hole K of the substrate 11. On one surface of the substrate 11, a rectangular plate-shaped fluorescence emission window member 16 from which fluorescence L <b> 2 from a phosphor layer 20 described later is emitted is disposed so as to close the opening of the recess D of the substrate 11. The excitation light incident window member 15 has an optical characteristic of transmitting the excitation light L1 from the excitation light source and reflecting the fluorescence L2 from the phosphor layer 20, and the fluorescence emission window member 16 is a fluorescent light described later. It has an optical characteristic of transmitting the fluorescence L2 from the body layer 20 and reflecting the excitation light L1 from the excitation light source.

  Then, by being surrounded by the light reflecting surface 10a of the excitation light incident window member 15, the fluorescence emission window member 16, and the light reflecting member 10, the excitation light L1 from the excitation light source and the fluorescence from the phosphor layer 20 described later are provided. A wavelength conversion space S where L2 crosses is formed, and the fluorescence that emits the fluorescence L2 upon receiving the excitation light L1 from the excitation light source on the light reflection surface 10a of the light reflecting member 10 in the wavelength conversion space S. A body layer 20 is formed. In addition, on the other side of the light reflecting member 10 opposite to the side on which the excitation light incident window member 15 is disposed, a heat exhausting member 25 made of heat radiation fins or the like is provided in contact with the light reflecting member 10. It has been.

  In the wavelength conversion type light source device according to the second embodiment, the material constituting the cylindrical base 11 and the light reflecting layer in the light reflecting member 10, the excitation light incident window member 15 and the fluorescence emitting window member 16 are configured. The material for forming the phosphor layer 20 and the thickness thereof are the same as those in the wavelength conversion type light source device according to the first embodiment.

In the wavelength conversion light source device described above, the excitation light L1 from the excitation light source is incident on the excitation light incident window member 15 and directly through the wavelength conversion space S, or the fluorescence emission window member 16 or the light reflecting member. After being reflected by the light reflecting surface 10a of the fluorescent layer 10, the phosphor layer 20 is irradiated. Then, by irradiating the phosphor layer 20 with the excitation light L1, fluorescence L2 having a longer wavelength than the excitation light L1 is emitted from the phosphor layer 20. Of the fluorescence L2, the light traveling toward the fluorescence emission window member 16 is emitted to the outside from the fluorescence emission window member 16, and the light traveling toward the light reflection member 10 is excited by the light reflection member 10 or the excitation. After being reflected by the light incident window member 15, the light is emitted to the outside from the fluorescence emission window member 16.
On the other hand, when the phosphor layer 20 is irradiated with the excitation light L1 from the excitation light source, a part of the energy generated by the excitation light L1 is converted into thermal energy in the phosphor layer 20, so that the phosphor layer 20 is heated. Although generated, the heat generated in the phosphor layer 20 is transmitted from the phosphor layer 20 to the exhaust heat member 25 through the light reflecting member 10, and is exhausted to the outside by the exhaust heat member 25. Thus, the phosphor layer 20 is cooled.

According to the above wavelength conversion type light source device, since the phosphor layer 20 is formed on the light reflection surface 10a in the light reflection member 10 that forms the wavelength conversion space S where the excitation light L1 and the fluorescence L2 intersect, By using a material having thermal conductivity as the material constituting the light reflecting member 10, heat generated in the phosphor layer 20 can be exhausted from the heat exhausting member 25 to the outside through the light reflecting member 10. Therefore, since the phosphor layer 20 can be cooled, high luminous efficiency can be obtained. In addition, since it is not necessary to mount a light emitting wheel or a rotation mechanism for rotating the light emitting wheel, the apparatus can be reduced in size.
The excitation light incident window member 15 has an optical characteristic of transmitting the excitation light L1 and reflecting the fluorescence L2, and the fluorescence emission window member 16 is an optical characteristic of transmitting the fluorescence L2 and reflecting the excitation light. Therefore, a high light utilization rate can be obtained.

FIG. 5 is an explanatory cross-sectional view showing the configuration of the main part of the wavelength conversion type light source device according to the third embodiment of the present invention. The wavelength conversion type light source device receives the excitation light L1 from the excitation light source and converts the wavelength. The excitation light L1 from the excitation light source on the inner surface of the substantially rectangular parallelepiped base 11 and a phosphor described later. A light reflecting member 10 having a concave part D having a partial spherical shape or a partial elliptic spherical shape formed with a light reflecting surface 10a for reflecting the fluorescence L2 from the layer 20 is provided. In the light reflecting member 10 of this example, a light reflecting layer (not shown) is formed on the inner surface of the recess D of the base 11, and the light reflecting surface 10a is formed by this light reflecting layer.
A rectangular plate-like window member 17 from which excitation light L1 from an excitation light source is incident and fluorescence L2 from a phosphor layer 20 described later is emitted on one surface of the base 11 in the light reflecting member 10 is It arrange | positions so that the opening of the recessed part D of the base | substrate 11 may be plugged up.

  Then, by being surrounded by the light reflecting surface 10a of the window member 17 and the light reflecting member 10, a wavelength conversion space S in which excitation light L1 from the excitation light source and fluorescence L2 from the phosphor layer 20 described later cross is formed. On the light reflecting surface 10a of the light reflecting member 10 in the wavelength conversion space S, a phosphor layer 20 that receives the excitation light L1 from the excitation light source and emits fluorescence L2 is formed. In addition, on the other surface of the light reflecting member 10 opposite to the surface on which the window member 17 is disposed, a heat exhausting member 25 made of a heat radiating fin or the like is provided in contact with the light reflecting member 10.

  In the wavelength conversion type light source device according to the third embodiment, the material constituting the cylindrical substrate 11 and the light reflecting layer in the light reflecting member 10 and the material and the thickness constituting the phosphor layer 20 are the same as those in the first embodiment. This is the same as that in the wavelength conversion type light source device according to the embodiment.

The window member 17 transmits the fluorescence L2 emitted from the phosphor layer 20, reflects the excitation light L1 from the excitation light source in an angle range equal to or greater than a specific incident angle, and has an angle range less than the specific incident angle. The optical characteristics of transmitting the excitation light L1 by the laser light in FIG. Here, the angle range above a specific incident angle, that is, the range of the incident angle that can reflect the excitation light L1 from the excitation light source is preferably 30 to 90 °, and more preferably 20 to 90 °. When the lower limit of the specific incident angle, that is, the incident angle at which the excitation light L1 from the excitation light source can be reflected is excessive, the amount of the excitation light L1 emitted through the window member 17 increases, and therefore the excitation light L1. It may be difficult to perform wavelength conversion with high efficiency.
As such a window member 17, a member in which a dielectric multilayer film made of TiO ₂ and SiO ₂ is formed on the surface of a plate-like translucent substrate can be used.

  Moreover, it is preferable that the window member 17 has an optical characteristic which reflects the fluorescence L2 radiated | emitted from the fluorescent substance layer 20 in an angle range more than another specific incident angle. Here, it is preferable that the range of the incident angle which can reflect the fluorescence L2 radiated | emitted from the fluorescent substance layer 20, for example, the angle range beyond another specific incident angle is 55-90 degrees, for example. According to such a configuration, only the fluorescence L2 emitted from the phosphor layer 20 is incident on the window member 17 in an angle range less than another specific incident angle via the window member 17. Therefore, light having high directivity can be obtained.

  For example, when the excitation light L1 is light in the blue region with a wavelength of 445 nm or less and the fluorescence L2 from the phosphor layer 20 is light in the green region with a wavelength of 500 to 570 nm, the spectral reflection characteristics of the window member 17 used are This is schematically shown in FIG. In the spectral reflectance curve diagram of FIG. 6, the vertical axis indicates the spectral reflectance (%), the horizontal axis indicates the wavelength (nm) of the incident light, and the solid lines a and a ′ indicate the spectral reflection when the incident angle is 0 °. The rate curve, broken lines b and b ′ indicate the spectral reflectance curve when the incident angle is 30 °, and broken lines c and c ′ indicate the spectral reflectance curve when the incident angle is 55 °. The window member 17 exhibits good transmittance with respect to light having a wavelength of 445 nm and light having a wavelength of 500 to 570 nm when the incident angle is 0 °, and converts light having a wavelength of 445 nm when the incident angle is 30 °. It shows good reflectivity for the light with a wavelength of 500 to 550 nm and good reflectivity for the light with a wavelength of 520 to 570 nm when the incident angle is 55 °. It is.

In the wavelength conversion type light source device described above, the excitation light L1 from the excitation light source is incident on the window member 17 in an angle range less than a specific incident angle, and directly or through the wavelength conversion space S or the window member 17 or light. After being reflected by the light reflecting surface 10a of the reflecting member 10, the phosphor layer 20 is irradiated. Then, by irradiating the phosphor layer 20 with the excitation light L1, fluorescence L2 having a longer wavelength than the excitation light L1 is emitted from the phosphor layer 20. Of this fluorescence L2, light that has entered the window member 17 in an angle range smaller than another specific incident angle is emitted to the outside from the window member 17, and the fluorescence L2 has an angle that is equal to or greater than another specific incident angle. The light incident on the window member 17 in the range is reflected by the window member 17 and the light reflecting surface 10a of the light reflecting member 10, and then emitted from the window member 17 to the outside.
On the other hand, when the phosphor layer 20 is irradiated with the excitation light L1 from the excitation light source, a part of the energy generated by the excitation light L1 is converted into thermal energy in the phosphor layer 20, so that the phosphor layer 20 is heated. Although generated, the heat generated in the phosphor layer 20 is transmitted from the phosphor layer 20 to the exhaust heat member 25 through the light reflecting member 10, and is exhausted to the outside by the exhaust heat member 25. Thus, the phosphor layer 20 is cooled.

According to the above wavelength conversion type light source device, since the phosphor layer 20 is formed on the light reflection surface 10a in the light reflection member 10 that forms the wavelength conversion space S where the excitation light L1 and the fluorescence L2 intersect, By using a material having thermal conductivity as the material constituting the light reflecting member 10, heat generated in the phosphor layer 20 can be exhausted from the heat exhausting member 25 to the outside through the light reflecting member 10. Therefore, since the phosphor layer 20 can be cooled, high luminous efficiency can be obtained. In addition, since it is not necessary to mount a light emitting wheel or a rotation mechanism for rotating the light emitting wheel, the apparatus can be reduced in size.
Further, since the window member 17 has an optical characteristic of reflecting the excitation light L1 in an angle range equal to or greater than a specific incident angle, a high light utilization rate can be obtained.
Further, since the window member 17 has an optical characteristic of reflecting the fluorescence L2 in an angle range equal to or greater than another specific incident angle, light with high directivity can be emitted.

Specific examples of the wavelength conversion light source device of the present invention will be described below, but the present invention is not limited to these examples.
According to the configuration shown in FIG. 5, a wavelength conversion type light source device having the following specifications was produced.
[Excitation light source]
The excitation light source is a blue light emitting diode that emits light having a wavelength of 445 nm, and its output is 30 W.
(Light reflecting member)
The base material is copper, and the overall dimensions of the base are 20 mm in length, 10 mm in width, and 5 mm in depth. The concave portion has a partial ellipsoidal sphere formed by an elliptical sphere having a major axis length of 7.9 mm and a minor axis length of 5.4 mm. In the cross section along the major axis, the concave portion opens from the center point of the elliptical sphere. The angle between two straight lines connecting the edges is 120 °. Further, the inner surface (light reflecting surface) of the recess is formed by a light reflecting layer made of silver and having a thickness of several hundred nanometers.
(Window member)
The window member has spectral reflection characteristics shown in FIG. In FIG. 7, the vertical axis represents the spectral reflectance (%) of incident light, the horizontal axis represents the wavelength (nm) of incident light, the curve a represents the spectral reflectance curve when the incident angle is 0 °, and the curve b represents The spectral reflectance curve when the incident angle is 20 °, and the curve c show the spectral reflectance curve when the incident angle is 30 °.
(Phosphor layer)
The phosphor layer is made of a silicone resin containing a β-sialon phosphor and has a thickness of 40 μm.

The light quantity of the fluorescence emitted from the window member in the wavelength conversion type light source device was measured as follows using the measurement system shown in FIG.
While the cooling air is supplied to the exhaust heat member 25 in the wavelength conversion type light source device by the fan 7, the excitation light from the excitation light source is inclined at an angle of 45 ° with the collimator lens 1 arranged on the optical path. The light enters the window member 17 in the wavelength conversion type light source device through the optical filter 2 and the focusing lens 3. Here, the optical filter 2 has an optical characteristic of transmitting the excitation light from the excitation light source and reflecting the fluorescence from the phosphor layer 20. Then, the fluorescence emitted from the window member 17 in the wavelength conversion type light source device enters the integrating sphere 5 through the optical filter 2 and the focusing lens system 4, and a light receiver (not shown) provided in the integrating sphere 5. As a result, the light quantity of the fluorescence was measured to be 4000 Lm (the luminous efficiency was 133 Lm / W), and it was confirmed that the fluorescence was emitted with high efficiency. Further, when the amount of fluorescent light emitted from the window member 17 was measured after 10 minutes had passed since the excitation light was incident on the window member 17, the amount of fluorescent light remained stable with no significant change. It was confirmed.

Based on the wavelength conversion type light source device, the surface temperature of the phosphor layer is simulated by changing the thickness of the phosphor layer by thermal structure analysis, and the surface temperature of the phosphor layer and the thickness of the phosphor layer. I investigated the relationship with. The results are shown in FIG. In FIG. 9, the vertical axis indicates the surface temperature (° C.) of the phosphor layer, the horizontal axis indicates the thickness of the phosphor layer, and a indicates the temperature when the temperature of the back surface (right side in FIG. 8) of the light reflecting member is 30 ° C. , B are those when the temperature of the back surface of the light reflecting member is 0 ° C. From this figure, it is understood that the surface temperature of the phosphor layer varies depending on the thickness of the phosphor layer.
Further, when the surface temperature of the phosphor layer when the temperature of the back surface of the light reflecting member was 30 ° C. was simulated, the surface temperature of the phosphor layer was 100 by forming the phosphor layer having a thickness of 55 μm or less. It was confirmed that the temperature was maintained below ℃.

DESCRIPTION OF SYMBOLS 1 Collimator lens 2 Optical filter 3 Focusing lens 4 Focusing lens system 5 Integrating sphere 7 Fan 10 Light reflection member 10a Light reflection surface 11 Base 12 Light reflection layer 15 Excitation light incident window member 16 Fluorescence emission window member 17 Window member 20 Fluorescence Body layer 25 Exhaust heat member D Recess K K Through hole L1 Excitation light L2 Fluorescence S Wavelength conversion space

Claims (7)

In the wavelength conversion type light source device that receives the excitation light from the excitation light source and converts the wavelength,
From the excitation light incident window member into which the excitation light from the excitation light source is incident, a phosphor layer that emits fluorescence upon receiving the excitation light incident through the excitation light incident window member, and from the phosphor layer A fluorescence emission window member from which the fluorescence is emitted, and a light reflection member on which the excitation light and a light reflection surface for reflecting the fluorescence are formed, the excitation light incidence window member, and the fluorescence emission window By being surrounded by the light reflecting surface of the member and the light reflecting member, a wavelength conversion space where the excitation light and the fluorescence intersect is formed,
The phosphor layer is formed on a light reflecting surface of the light reflecting member in the wavelength conversion space,
The excitation light incident window member has an optical characteristic of transmitting the excitation light and reflecting the fluorescence, and the fluorescence emission window member has an optical characteristic of transmitting the fluorescence and reflecting the excitation light. A wavelength conversion type light source device comprising:   The light reflecting member is a cylindrical member having a light reflecting surface formed on an inner peripheral surface, and the excitation light incident window member and the fluorescence emitting window member are closed so as to close the openings at both ends of the light reflecting member. The wavelength conversion type light source device according to claim 1, wherein:   The light reflecting member has a recess having a light reflecting surface formed on the inner surface and has a through hole that communicates with the recess, and the excitation light incident window member closes the opening of the through hole of the light reflecting member. The wavelength conversion type light source device according to claim 1, wherein the fluorescence emission window member is disposed so as to close the opening of the concave portion of the light reflecting member. In the wavelength conversion type light source device that receives the excitation light from the excitation light source and converts the wavelength,
A light reflecting member having a recess having a light reflecting surface formed on the inner surface, and excitation light from an excitation light source disposed so as to close the opening of the recess of the light reflecting member and fluorescence from a phosphor layer described later A light reflecting member formed with a window member from which light is emitted, a phosphor layer that receives excitation light incident through the window member and emits fluorescence, and a light reflecting surface that reflects the excitation light and the fluorescence And is surrounded by a light reflecting surface in the window member and the light reflecting member, thereby forming a wavelength conversion space where the excitation light and the fluorescence intersect,
The phosphor layer is formed on a light reflecting surface of the light reflecting member in the wavelength conversion space,
The wavelength conversion type light source device, wherein the window member has an optical characteristic of reflecting the excitation light in an angle range greater than a specific incident angle.   5. The wavelength conversion type light source device according to claim 4, wherein the window member has an optical characteristic of reflecting the fluorescence in an angle range equal to or greater than another specific incident angle.   6. The wavelength conversion type light source device according to claim 1, wherein the light reflecting member has thermal conductivity.   7. The wavelength according to claim 1, wherein the phosphor material constituting the phosphor layer emits fluorescence upon receiving excitation light in a blue region having a wavelength of 445 nm or less. Conversion type light source device.

Images